The operative approach to adrenal incidentalomas depends on the subclinical hormoneactivity and the risk of malignancy. In our 18 patients there were two pheochromocytomas (3 and 5 diameter), one with subclinical hormoneactivity and three malignancies, an adrenocortical carcinoma, a metastasis without primary and a lymphoma. The malignant tumors were larger than 5 cm. As tumors smaller than 3 cm are usually benign they should be observed. Because of the risk of malignancy there is a relative indication to operate on larger tumors.